1. Field of the Invention
The present invention relates to an electronic element wafer module and a method for manufacturing the electronic element wafer module. In the electronic element wafer module, a plurality of lenses for focusing incident light or a plurality of optical function elements for directing output light straight and refracting and guiding incident light in a predetermined direction; and an image capturing element including a plurality of light receiving sections corresponding to respective lenses for performing a photoelectric conversion on and capturing an image of image light from a subject, or a light emitting element for emitting output light and a light receiving element for receiving incident light corresponding to respective optical function elements, are modularized (integrated) in a plural number. Further, the present invention relates to an electronic element module manufactured by simultaneously cutting the electronic element wafer module into each of the electronic element modules, and a method for manufacturing the electronic element module. Still further, the present invention relates to an electronic information device, such as a digital camera (e.g., a digital video camera or a digital still camera), an image input camera (e.g., a car-mounted camera), a scanner, a facsimile machine, a television telephone device, a camera-equipped cell phone device or a personal digital assistant (PDA), including a sensor module as an image input device (e.g., a car-mounted camera) used in an image capturing section of the electronic information device. The sensor module functioning as the electronic element module is manufactured by simultaneously cutting a sensor wafer module into individual pieces, the sensor wafer module functioning as the electronic element wafer module including: an image capturing element including therein a plurality of light receiving sections for performing a photoelectric conversion on and capturing an image of image light from a subject; and a lens for forming an image of incident light on the image capturing element, which are modularized (integrated) in a plural number. Further, the present invention relates to an electronic information device, such as a pick up apparatus, including the electronic element module used in an information recording and reproducing section thereof.
2. Description of the Related Art
In a conventional sensor module as an electronic element module of this type, a lens section for focusing incident light and an image capturing element corresponding to the lens section, which includes therein a plurality of light receiving sections for performing a photoelectric conversion on and capturing an image of incident light from a subject, are modularized. In the conventional sensor module, a current light shielding treatment for the image capturing element is mostly performed on the individualized sensor modules. The current light shielding treatment is performed, for example, by covering the individualized complete sensor module with a light shielding holder, by applying a light shielding material on the periphery and top portions of the sensor module, and by piling up light shielding blocks functioning as a sensor module. As one of the conventional light shielding treatments, Reference 1 proposes the application of a light shielding material on the periphery and top portions of the sensor module. In addition, Reference 2 proposes a process method for piling up light shielding blocks. Each of the proposals will be described hereinafter.
FIGS. 7(a) to 7(e) are each an essential part longitudinal cross sectional view illustrating each manufacturing step of the conventional semiconductor image capturing element of Reference 1.
As illustrated in FIG. 7(a), an image capturing area 102 in the middle portion and a peripheral circuit area 103 in an outer circumference area adjoining the image capturing area 102 are formed in an upper surface 101a of a semiconductor substrate 101. A plurality of electrode sections 104 are disposed on a further outer circumference side of the peripheral circuit area 103 on the upper surface 101a. Further, a plurality of microlenses 105 are provided on image capturing area 102 for focusing incident light on each light receiving section. Each of the plurality of microlenses 105 is provided to correspond to each pixel.
Here, as illustrated in FIG. 7(b), a bump 106 is provided on each of the electrode sections 104 on the further outer circumference side of the peripheral circuit area 103. The bump 106 may be formed, for example, by a wire bonder with a conductive wire. Connection surfaces of the bumps 106 are pressed by a plate-shaped metal plate after the bumps 106 are formed. The plate-shaped metal plate includes an opening larger than an optical member 108, which is composed of a lens section. Thus, the connection surfaces of the bumps 106 may be pressed by the plate-shaped metal plate, so that the height becomes even and the connection surfaces of the bumps 106 are planarized to be easily electrically connected with the conductive wire.
As illustrated in FIG. 7(c), a light shielding film 109 is provided in advance in a side surface area of an optical member 108 constituted of the lens section. The light shielding film 109 is formed with a metal or resin material which has a light shielding effect. Further, the optical member 108 has a shape that covers at least the image capturing area 102.
Next, as illustrated in FIG. 7(d), a transparent adhesive member 110, which is cured by ultraviolet rays, is applied in such a manner to cover the microlenses 105 and the peripheral circuit area 103 therearound in each semiconductor element 107. The transparent adhesive member 110 can be applied, for example, by painting, printing and stamping.
Further, as illustrated in FIG. 7(e), the optical member 108, which is constituted of the lens section, is disposed with respect to the image capturing area 102, which is applied with the transparent adhesive member 110. Subsequently, while the upper surface of the optical member 108 and the upper surface of the image capturing area 102 are maintained to be parallel, the optical member 108 is pressurized from the upper surface. Next, ultraviolet rays of wavelengths curing the transparent adhesive member 110 are irradiated on the upper surface side of the optical member 108 as illustrated by arrows 111. Because of the irradiation, the image capturing area 102 and the optical member 108 are adhered by the transparent adhesive member 110. As a result, the optical member 108 is adhered on the semiconductor element 107, and a semiconductor image capturing element 100A is obtained.
A plurality of semiconductor image capturing elements 100A, which are manufactured as described above, are in a semiconductor wafer shape, and adjacent semiconductor elements 107 are diced. By the dicing, individualized semiconductor image capturing element 100A can be obtained as illustrated in FIG. 7(e). As a result, the optical member 108 is adhered by the transparent adhesive member 110 directly on the microlenses 105 of the semiconductor element 107, thereby achieving the thinning. In this state, even if the transparent adhesive member 110 flows into the peripheral circuit area 103, it will not be a problem since the bump 106 is connected onto the electrode section 104 and the bump 106 is formed higher than the height of the surface 101a of the transparent adhesive member 110, thereby providing no possibility of failing to adhere the conductive wire and achieving a high reliability. Further, it is only required to form the bump 106 on the electrode section 104 prior to the step of adhering the optical member 108. As a result, the productivity is increased without spoiling the mass productivity.
Subsequently, as illustrated in FIG. 8, a light shielding member 112 is further provided. The light shielding member 112 includes an exposed area 110a of the transparent adhesive member 110 and a side surface area 108a of the optical member 108. The light shielding member 112 is formed above the peripheral circuit area 103 in such a manner not to cover the electrode section 104 and the bump 106. In this case, the light shielding member 112 is applied such that the surface 112a of the light shielding member 112 is lower than the height of a connection surface 106a of a tip portion of the bump 106.
Next, FIGS. 9 and 10 illustrate the process method for piling up light shielding blocks as a light shielding treatment for the conventional sensor module.
FIG. 9 is an exploded perspective view illustrating a conventional compound eye image capturing apparatus of Reference 2 in an assembling state. FIG. 10 is a longitudinal cross sectional view of a holder member and a light shielding block portion, holding an optical lens array of the compound eye image capturing apparatus 200 in FIG. 9.
In FIGS. 9 and 10, a conventional compound eye image capturing apparatus 200 includes: an optical lens array 203; a holder member 204; a light receiving array 205; a light shielding block 206; and a frame member 207. The optical lens array 203 is formed with nine optical lenses 201 of three rows by three columns with respective optical axes L parallel to one another, integratedly formed as one side convex lenses on a lower surface of a single transparent substrate 202. The holder member 204 holds the optical lens array 203 in such a manner to hold it from top and bottom. The light receiving element array 205 is disposed below the optical lens array 203 to capture nine images formed by the optical lenses 201. The light shielding block 206 is disposed between the optical lens array 203 and the light receiving array 205 to divide a space between the optical lens array 203 and the light receiving array 205 on a surface orthogonal to the optical axis L so that light output from the optical lenses 201 will not interfere with one another. The frame member 207 is disposed between the light shielding block 206 and the light receiving array 205, and functions as a spacer for surrounding the light receiving array 205 like a picture frame to prevent the light shielding block 206 from touching the light receiving array 205.
The holder member 204 is constituted of an upper plate member 204a and a lower frame member 204b. The lower frame member 204b includes a groove formed therein for mating with an edge portion of the optical lens array 203. The upper plate member 204a is configured as an aperture member for shielding unnecessary incident light to the optical lenses 201 by forming apertures 204c of a predetermined size at nine positions corresponding to the optical lenses 201.
The light shielding block 206 is configured by laminating six sheet metal unit plates Pa which are 120 μm thick and further laminating thereon two sheet metal unit plates Pb which are 80 μm thick. That is, eight unit plates Pa and Pb of two different thicknesses are laminated. As a result, the light shielding block 206 of 880 μm total thickness is formed. The length consisting of the thickness of the light shielding block 206 and the thickness of the frame member 207 surrounding the light receiving array 205 and the holder member 204 of the optical lens array 203, is configured to be equal to the optical length of the optical lens 201.
Next, as a reference, a method for forming a light shielding film will be described as in Reference 3, where the light shielding film is formed on a surface except for above a light receiving lens.
FIG. 11 is an essential part longitudinal cross sectional view of a remote control light receiving module of Reference 3, which is one of conventional optical function modules.
As illustrated in FIG. 11, a remote control light receiving module 300, which is one of conventional optical function modules, is configured of: a lead frame 301; an infrared ray light receiving element 302 thereon; a processing circuit 303 for processing signals output from the infrared ray light receiving element 302; chip parts necessary for the processing circuit 303 installed and connected thereto; and a resin 304 for molding the above sections. A light shielding film 306 is formed on a flat part of the resin 304 except for on a light receiving lens portion 305. The light receiving lens portion 305 is molded by a material with the same quality as that of the resin 304.
The lead frame 301 is formed with a metal plate material, and its main component is any of Fe, Ni, Cu, or an alloy thereof. A surface of the lead frame 301 is coated with a film of Ag. As the form of the lead frame 301, the molded inside of the lead frame 301 is configured of several of separate parts in order to support the entire mold by a group of externally protruding terminals 307 as well as to electrically connect with the infrared ray light receiving element 302 and the processing circuit 303. The thickness of the lead frame 301 is 300 μm or more.
The infrared ray light receiving element 302 is disposed such that the center of the infrared ray light receiving element 302 and the center of the light receiving lens portion 305 are aligned. The size of the infrared ray light receiving element 302 can be 2 mm square or less depending on the light focusing performance of the light receiving lens portion 305. If the size becomes significantly larger than 3 mm square, the capacitive component of the infrared ray light receiving element 302 may become too large, causing the processing circuit 303 to operate improperly. Infrared rays entering the infrared ray light receiving element 302 through the light receiving lens portion 305 generate current signals at the infrared ray light receiving element 302. The current signals generated are signal-processed at the electrically connected processing circuit 303. The processing circuit 303 includes functions such as converting the input current signals into voltages, amplifying, filtering noise signal components except for remote control signals, detecting and rectifying.
The resin 304 is molded in such a manner to cover the processing circuit 303 and infrared ray light receiving element 302 installed on the lead frame 301. At the same time the resin 304 forms the light receiving lens section 305. The resin 304 has a function of cutting visible light, which rapidly decreases light of approximately 800 nm or less. However, the resin 304 does not completely prohibit the light with a wavelength of approximately 800 nm or less from passing, but some extent of optical noise occurs from strong light. Therefore, in this case, the distance is 500 μm or more from the infrared ray light receiving element 302 to the flat portion of the light receiving lens section 305 except for the convex portion. For example, an epoxy material is used for the resin 304. When a visible light cutting material with transmissivity for infrared rays from approximately 820 nm of an infrared ray wavelength is used for the resin 304, the transmissivity of 95% or more can be achieved at the wavelength band of 950 nm.
The light receiving lens section 305 is a lens for focusing infrared ray light transmitted from a remote control transmitter. The light receiving lens section 305 is a half sphere or a shape close to it, for example. The light receiving lens section 305 focuses infrared ray light which enters the light receiving lens section 305 onto the infrared ray light receiving element 302. Because of the effect of the lens, the effective light focusing effect of the infrared ray light, which enters the light receiving lens section 305, can be determined based on the refractive index for each wavelength, transmissivity, and light receiving area of the infrared ray light receiving element 302, which can be determined by the area accounting for the infrared ray light entering the light receiving lens section 305 in the vertical direction and the material. Herein, the effective light focusing effect of approximately 3 to 4 magnifications can be achieved by appropriately setting the refractive index, transmissivity, the area of the infrared ray light receiving element 302, and the area of the light receiving lens section 305, with respect to air in the vicinity of 950 nm.
The light shielding film 306 is formed on the surface except for on the portion of the light receiving lens section 305, which is a surface for receiving the infrared ray light. For example, a black-colored epoxy resin can be used as a material for the light shielding film 306. Besides, ABS, PP and PC can also be used as the material for the light shielding film 306. In addition, lacquer and enamel paints can be used as the material for the light shielding film 306. However, if a water-soluble paint, such as acrylic paint, is used as the material for the light shielding film 306, and if a hydrophilic treatment is not performed on the surface of the molded resin, there is a high possibility that spots will appear. For paint, the order of several μm may not be enough as the film thickness of the light shielding film 306, and spots will appear. In such a case, there may be a light scattering effect, but the light may not be decreased.
Thus, when the light shielding film 306 is formed on the surface except for on the light receiving lens section 305, the light receiving lens section 305 is covered with a mask. Next, using the mask, the light shielding film 306 is formed on the surface except for on the light receiving lens section 305. Subsequently, the mask is removed.
Reference 1: Japanese Laid-Open Publication No. 2008-92417
Reference 2: Japanese Laid-Open Publication No. 2007-180653
Reference 3: Japanese Laid-Open Publication No. 2002-246613